Definition of Ktrans and FA Thresholds for Better Assessment of Experimental Glioma Using High-field MRI: A Feasibility Study

To define K-trans and fractional anisotropy (FA) thresholds in correlation to histology for improved magnetic resonance imaging (MRI) tumor assessment in an animal model of brain glioma. Twelve rats underwent 4.7 T MRI at day 10 after tumor implantation. Anatomical scans (T-2, T-1 at 8 min after double dose contrast application) as well as dynamic contrast-enhanced (DCE) imaging with calculation of K-trans and diffusion tensor imaging (DTI) with calculation of FA were performed. T-2- and T-1-derived tumor volumes were calculated and thresholds for K-trans and FA were defined for best MRI tumor assessment correlated to histology. Tumor volumes were 159 +/- 14 mm(3) (histology), 126 +/- 26 mm(3) (T-1 with contrast, r = 0.76), and 153 +/- 12 mm(3) (T-2, r = 0.84), respectively. K-trans- and FA-derived tumor volumes were 160 +/- 16 mm(3) (for K-trans A(3) 0.04 min(-1), r = 0.94), and 159 A +/- 14 mm(3) (for FA A pound 0.14, r = 0.96), respectively. DCE-MRI and DTI with calculation of K-trans and FA maps allow very precise brain glioma assessment comparable to histology if established thresholds for the given tumor model are used.